The Life and Times of Jeff Squyres

March 2004 Archives

March 3, 2004

He's probably thinking "Mmm... good sandwich."

News Radio was on A&E last night! It hasn’t been on in quite a long time. God bless Tivo for catching it…

XM Radio is playing a really, really lame version of “All the Things She Said” by t.A.T.u. right now — the song itself is fine, but this mix of it is pretty awful. It’s like whatever DJ did this took the song, slowed it down to 1/4 speed, and added a lot of space between the words. Weird.

March 5, 2004

Tomorrow's the big day, eh Dave?

It is done. I submitted it. 4:40pm. I can sleep again!

Ok, well, it’s not done done. I still have a little more work on it to go. A few more results to put in, a little more polish on one part of the conclusion, and a million little details that no one will notice except me. Hopefully we’ll be good to go. Yummy!

Slimy slimy slimy

March 15, 2004

"dash oh": bite me

So I wasted a valuable afternoon today because of ickyness in LAM/MPI 6.5.9.

I have the AVIDD-B cluster all to myself to run dissertation performance results today. Mainly, I’m comparing LAM 6.5.x performance to LAM 7.x performance. For what I’m doing the two results should be pretty much the same — the whole point of my dissertation is that I added a bunch of great abstractions into LAM but without any performance penalty. I had it about 2 weeks ago, too, for the same reason. But a bunch of my numbers got borked 2 weks ago — namely the 6.5.9 numbers were way worse than they were supposed to be. Specifically: 7.x performed way better than 6.5.9 on gigabit ethernet.

I thought that it was just a simple missing [memcpy] optimization that we debuted in 7.x. So I added that optimization in my copy 6.5.9 today and re-ran the results. Same crappy performance.

Wha…?

So I removed the optimization from my copy of 7.x, and the same great performance was there. i.e., there was still a huge performance difference between 6.5.9 and 7.x. I spent several hours trying to figure out what the heck the difference was. I even roped Brian into it — we couldn’t remember what optimization we had added that gave such a huge performance increase in 7.0.

While I was going through Changelogs, it hit me. The stupid “[-O]” option to 6.5.x’s [mpirun] — if you don’t explicitly tell LAM 6.5.9 to no do it, it’ll always put data on the network in big endian (“network”) order. This really sucks on Linux boxen, obviously. So you specify “[-O]” to [mpirun] and tell it not to do that. In 7.x, we handle this automatically. Specifically, I had totally forgotten about this option, and none of my 6.5.9 results were run with “[-O]”. Hence, all those results were showing the effects of 2x byte swapping.

ARRRGGGGHHHH!!!!

And I knew about this option. It’s bitten me before. And I’ve scolded users to use it. I wasted several valuable hours on the cluster figuring this out (and it’s why my results weren’t right two weeks ago). Grrr…

Stinkbutt

So I’m sitting here waiting for my jobs to run on AVIDD-B. They’re going to run for quite a long time, and I’ll probably be up all night shepharding the jobs, ensuring that they keep running. So it’s blog time.

Here’s something I don’t understand: people who throw cigarette butts out car windows.

It always ticks me off when I’m driving behind someone and they throw a butt out their window. I always feel like screeching to a halt, picking up the butt, and following the car until they stop — perhaps at the next light. Then getting out and walking up to their window, knocking on it, and saying “Here — you dropped something.” And throwing the butt back at them.

Why do cigarette smokers feel like the world is their ashtray?

If you’re smoking in your car, your car is already going to smell bad. There’s no good reason to not use your ashtray. Laziness does not count (not wanting to empty the ashtray).

Throwing a butt out the window is littering. Plain and simple. Why does society seem to attach a big stigma to all forms of littering… except for cigarette butts?

Butt-throwers should be condemned to pick up all the butts along the sides of highways. It’s surprising, disappointing, and disgusting how many butts there are along our roadways. I remember being a Boy Scout and doing various community projects such as picking up trash along roads and highways — cigarette butts were, by far, the largest collection of trash that we would pick up.

Give me 4 255-sided die and I'll get you some IPs

We’re having our monthly LAM 10 meeting this week at IU. I didn’t do much today because I was stuck doing AVIDD runs (see previous entry about “dash oh” woes).

My ibook was supposedly ordered last week. I anticipate seeing it in a month or so. That’s right, I’m making the leap to an OS X laptop. Woo hoo!

I served my last “weekend warrior” days (although they weren’t actually on a weekend — I made them up during a week) last week. I officially become a civilian this Friday. What am I going to do without a monthly reminder to get my hair cut?

I made a similar statement at lunch today (“what am I going to do without a monthly reminder to get my hair cut?”). One of the people that I was eating with looked at me funny and said, “The Army sent you some kind of reminder to get your hair cut every month?” “Yes,” I said, “There is a sophisiticaed image analysis program that you can hook up to a web camera on your PC (I run this on my computer) that takes pictures of your head. When it detects that your hair is longer that it is allowed to be by Army regulation, it sends an e-mail to you and your commander, letting you know that it’s time to get a haircut. They have a similar program for the Air Force, but they add 3 inches to the allowable hair length size.” “Wow,” he said, fully believing me. “The Army is really advanced!” I’m such a twerp. ☺

I fixed some long-standing issues in env-switcher that Jeremy E. has been whining about forever.

We switched all the LAM and MPI-related CVS repositories to Subversion this weekend. We ran into a few minor glitches here and there (this umask issue was the most insidious), but it seems to be going ok. Except for the fact that Ralph G. can’t seem to get subversion to compile properly on his new OS X laptop (he was trying just about all day today). Bonk.

Guess what? I got a fever; and the only perscription is cowbell!

March 25, 2004

Props! Huge props!

Let the record show that I ower Brian 3 beers of his choice (size/quantity and brand unspecified) for, at a moment’s notice, dropping everything and figuring out how to use gcov (in parallel, no less) and calculate how much coverage we have in the LAM test suite.

This is the longest friggen’ document that I have ever written by myself. It’s a logistical nightmare! Try writing a highly technical, highly complex 350+ page document and see how hard it is to keep everything consistent. Woof! I can’t even imagine writing this without decent editing tools. Using Word, for example, would have totally — TOTALLY — sucked.

Subversion has been an enormous help — I converted my dissertation repository from CVS to SVN a few months ago. With all the results that I had to run, and with the number of files that I had to move/rename/delete, and with all the binary files that I am keeping in the repository, CVS would have sucked. Big time. Subversion rocks.